Image guided medical and surgical procedures utilize patient images obtained prior to or during a medical procedure to guide a physician performing the procedure. Recent advances in imaging technology, especially in imaging technologies that produce highly-detailed, two, three, and four dimensional images, such as computed tomography (CT), magnetic resonance imaging (MRI), fluoroscopic imaging, positron emission tomography (PET), and ultrasound imaging (US) has increased the interest in image guided medical procedures.
Image guided surgical techniques have been used to assist surgeons and individuals in various surgical procedures. Various image based navigation systems include U.S. Pat. No. 6,470,207, entitled “Navigational Guidance Via Computer-Assisted Fluoroscopic Imaging”, issued Oct. 22, 2002, which is hereby incorporated by reference in its entirety; and image based systems such as the STEALTHSTATION, and various improvements such as the TREON and ION sold by Medtronic Surgical Navigation Technologies of Louisville, Colo. Generally, the procedures and instruments used with image guided surgery allow for visualization or virtual visualization of surgical instruments and various anatomical portions in relation to preacquired or real-time images. Representations of the instruments and implants are generally super-imposed over the preacquired or real-time images of the patients anatomy. Nevertheless, these systems generally require registration of the image data to the patient such that the image data used to guide the procedure matches the patient's intra-operative orientation known as patient space.
Various medical procedures may benefit from image-based navigation systems. For example, a spinal fusion procedure may be performed according to various known techniques. For example, an image based navigation system, such as those discussed above, may be used to assist in a spinal fusion procedure. Nevertheless, the navigation system generally requires the acquisition of a patient image and a registration of the patient image with the surgical patient space to ensure proper guiding and navigation of the instruments and implant portions. Therefore, the image based navigation systems require use of various image acquisition components in an operative procedure, such as the fluoroscopic device, a magnetic resonance imaging (MRI) device, or other image capturing devices. These images are then registered relative to the patient, generally using known registration techniques, such as automatic registration, user guided registration, 2D or 3D registration, point registration and surface registration. Dynamic referencing may also be used to track patient movement during the procedure.
In the alternative, a substantially open procedure may be used to perform the spinal fusion, or anterior cruciate ligament replacement, acetabular implantation, femoral implantation, spinal disc nuclease replacement, spinal disc replacement, and the like. For example, the soft tissue surrounding the spine, particularly a posterior portion of the spine, may be substantially opened or removed such that an “open” view of the spine may be obtained. After the soft tissue has been opened to create the operative passage, the procedure may continue with the user, such as a surgeon, having a clear view of the surgical area. Nevertheless, the open procedures require a large incision and movement of soft tissue. This large incision, movement of soft tissue, and necessary closures, often may require an extended recovery.
Open procedures may also be supplemented with various systems, such as a device to mechanically customize connecting rods by MEDIVISION of Germany. This system may allow for bending of connecting rods to fix a selected geometry. The selected geometry may be determined using any appropriate mechanism, such as a coordinated system or registration system to determine the appropriate angle and shape of the rod.
Alternatively, a substantially percutaneous and/or minimally invasive procedure may be used to position a construct to perform a spinal fusion. During the percutaneous procedure, the various components of the construct are mechanically interconnected or held with an alignment instrument. For example, a head of a pedicle screw may be aligned with such an instrument. Once aligned, the instrument mechanically guides a connector member to interconnect with each pedicle screw.
Although this may be achieved with little difficulty when a low or single level construct, such as a low number of elements are used, such as interconnecting two pedicle screws, it becomes more difficult when attempting to interconnect multi-level constructs, such as more than two pedicle screws. In addition, if the screws are implanted in a selected non-aligned position, such as required by various procedures, the interconnection by a connector is also difficult because the alignment by mechanical means becomes more complex and difficult to achieve. Further, having a constrained geometry increases the complexity. A constrained geometry requires the precise alignment of a plurality of portions that is complex in a percutaneous procedure using mechanical interconnections for alignment.
Therefore, it is desirable to provide a method and apparatus for performing surgical navigation of a percutaneous procedure to implant a selected construct. It is also desirable to provide a surgical navigation apparatus and method for generally planning and confirming an assembly of a construct percutaneously to substantially minimize or reduce trauma to the soft tissue and reduce the size of the incisions required to access the anatomical portions. It is also desirable to perform an imageless surgical navigation procedure that does not require registration of image data with patient space.